HT I-V600 - Typical Errors on I-V Curves and Troubleshooting

I-V600
EN - 76
11.2. TYPICAL ERRORS ON I-V CURVES AND TROUBLESHOOTING
Measurement
Event
Troubleshooting
Good measurement
• The measured curve extrapolated
to STC (blue) and the curve as
declared by the manufacturer
(black) of the modules match.
• No error, save data and
move to next string to test
Low short circuit current
• Irradiance sensor oriented
differently than the string under test
• Reflections on the irradiance sensor
• Wrong module selection at
configuration of PV system
• Environmental contaminants on
modules (soiling, dirt, snow, debris)
• Far distance obstruction (shading)
• Aging
• Orient the irradiance sensor
properly
• Set the instrument properly
• Clean the modules
• Remove the obstructions
• Check the modules for
blindness, humidity, etc.
• Replace affected modules
High short circuit current
• Irradiance sensor oriented
differently than the string under test
• Reflections on the irradiance sensor
• Dirt on the irradiance sensor
• Wrong module selection at
configuration of PV system
• Irradiance sensor defect
• Orient the irradiance sensor
properly
• Clean the irradiance sensor
• Remove the obstructions
• Check the irradiance sensor
for blindness, humidity, etc.
• Set the instrument properly
• Replace affected sensor
Low open circuit voltage
• Low temperature measurement
• Wrong numbers of module
selection at configuration of PV
system
• Shorted bypass diodes
• Attach the thermocouple
properly to a typical
temperature location
• Select the AUTO mode
• Set the instrument properly
• Replace affected modules
Low current ratio Impp/Isc
• Soiling across modules
• Tapered shades
• Small current mismatch
• Degradation of cell shunt resistance
• Clean the modules
• Un-shade the modules
• Check that currents match
• Replace affected modules